Construction cranes are towers in the sky – except when they collapse. Our first story examines three disasters in Seattle, Manhattan and Bangkok. Three disasters: three different reasons for collapse. We examine what went wrong. The Artz Pedregal Mall in Mexico City had only been open a few months before the cantilevered section of the structure came crashing to the street below. How could a brand new building fail so dramatically? What’s so precarious about cantilever designs?